1. Field of the Invention
The present invention relates to a method of operating a searcher in a mobile communication system.
2. Background of the Related Art
Typically, a code-division multiple access (CDMA) mobile communication system includes a mobile station and a base station. A CDMA signal modulated by and transmitted from the mobile station is received at the base station. The base station demodulates the CDMA signal so as to obtain the original signal. There is a pilot signal for synchronization and power control as one type of the CDMA signal. The pilot signal is a signal spread with a PN code sequence inherent to a terminal, and transmitted to the base station. The base station can demodulate other types of received signals by finding respective time delays, e.g., PN offsets, of multipath components of the pilot signal after searching multi-path pilot signals. In order to find the PN offsets, a searcher despreads the multi-path pilot signals with all PN offsets, averages respective energies of the despreaded pilot signals, and selects, as the PN offsets, PN offsets of averaged energies greater than a specified threshold value among the averaged energies.
Conventionally, there are respective searchers coupled to M channel elements.
Due to the characteristics of a data burst randomizer (DBR) on an IS-95-A/B reverse link, data is transmitted during two 1.25 ms sub-periods of 20 ms transmission period if the data transmission rate is lowest (for instance, 1200 or 1800 bps), and data may be not transmitted during other sub-periods of the 20 ms period. However, according to the conventional technology, since respective searchers are essentially coupled to M channel elements and thus the searchers cannot be shared other channel elements, the searchers may unnecessarily operate even in a period when a corresponding channel element does not have receiving data according to an operation of the DBR, resulting in an inefficient search operation.